Doctors administering stem cells might have no expertise in the condition they're trying to treat, and the cells themselves might be derived from questionable or discredited sources - if the treatment contains any stem cells at all.
"The stem cell treatments offered by these clinics have not been through the (U.S. Food and Drug Administration) approval process, so their safety and efficacy has not been systematically tested or documented. It's a 'buyer beware' situation," said lead researcher Emma Frow. She is an assistant professor of biological and health systems engineering at Arizona State University in Tempe.
"Also, these treatments are usually not reimbursed by insurance companies, so consumers have to pay out of pocket," she said.
Dodgy stem cell treatments can be dangerous. Three people have been blinded by stem cell injections intended to treat their macular degeneration, Frow said, while other cases have raised cancer concerns.
In November, the FDA issued a warning letter to San Diego-based Genetech after a dozen patients in three states were hospitalized with serious bacterial infections after receiving injections of umbilical cord blood purportedly containing stem cells. The products were tainted with E. coli and other dangerous bacteria.
A Variety of Ailments and Workers
Frow and colleagues identified 169 stem cell clinics in the southwestern United States. They cataloged the treatments being offered and the medical personnel staffing each center.
About a quarter of the clinics focused only on stem cell treatments.
"For the other 75%, stem cell treatments are one among some or many different possible treatment options at the clinic - for example, a sports medicine clinic that lists stem cells as just one among a whole roster of different treatment options for sports injuries," Frow said.
The study showed that stem cell clinics are operated by a wide variety of health care workers.
Nearly three-quarters of employees at clinics that focus solely on stem cells are doctors with either an M.D. or D.O. degree, researchers said.
They found that 14% of employees were either chiropractors or naturopaths; 7% had some other medical qualification; 5% had a graduate degree, and 2% had unspecified qualifications.
But even fully credentialed doctors might not be specialists in the conditions that their clinics promise to treat, researchers said.
"Specialists in orthopedics and sports medicine are more likely to restrict stem cell treatments to conditions related to their medical specialties, while care providers with specialties in cosmetic or alternative medicine are more likely to treat a much wider range of conditions with stem cells," Frow said.
Providers administering stem cells had a wide range of specialties, including family practice, internal medicine, anesthesiology, general surgery, cosmetic surgery, dermatology, sports medicine, acupuncture and herbal medicine.
Fat tissue was the stated source of stem cells for nearly two-thirds of the clinics, according to the study. Fat-derived stem cells were used to treat a wide range of illnesses, including neurodegenerative disorders, heart problems, gastrointestinal complaints, diabetes and muscular dystrophy.
Treatments derived from fat tissue may need FDA approval, and none has been granted, researchers said.
"Most of the businesses we profiled are likely not offering treatments that consist of pure stem cell preparations," Frow said. "The clinics usually don't make much information available on their websites, but the typical methods they mention for extracting and preparing the most common types of treatments on offer don't result in pure preparations of stem cells."
Watch For 'Cure-all' Claims
If you're interested in stem cell therapy, pass on clinics that promote the treatments as a wonder drug, experts advised.
"If you see a business marketing stem cell treatments for 30 or 40 or 50 diseases, that's eyebrow-raising," said Leigh Turner, an associate professor at the University of Minnesota Center for Bioethics in Minneapolis. "If you see someone who's been practicing for years as a cosmetic surgeon claiming to treat ALS or spinal cord injuries, it's highly unlikely they've got something meaningful to offer."
Frow offered a series of questions that people considering stem cell treatment can ask:
How many different conditions does the clinic offer to treat with stem cells?
Is the clinic participating in a formal, registered clinical trial using stem cells to treat your specific condition? (If so, you should not have to pay out of pocket for the treatment.)
Does the medical expertise of the doctor fit well with the specific condition for which you are seeking treatment?
Unfortunately, stem cell clinics wield flashy marketing featuring personal testimonials aimed at desperate people who suffer from chronic and incurable conditions, said Turner, who wasn't involved with the study.
"People who are desperate or family members of someone who is ill or injured, they're looking for messages that there are treatments out there," he said.
The FDA has been saying for years that it plans to become actively engaged in the regulation of stem cell clinics, but Turner isn't holding out hope.